/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements. See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership. The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the  "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
/*
 * $Id$
 */
package wx.xml.xalan.xml.dtm;

/**
 * Specifies values related to XPath Axes.
 * <p>The ancestor, descendant, following, preceding and self axes partition a
 * document (ignoring attribute and namespace nodes): they do not overlap
 * and together they contain all the nodes in the document.</p>
 */
public final class Axis {

    /**
     * The ancestor axis contains the ancestors of the context node;
     * the ancestors of the context node consist of the parent of context
     * node and the parent's parent and so on; thus, the ancestor axis will
     * always include the root node, unless the context node is the root node.
     */
    public static final int ANCESTOR = 0;

    /**
     * the ancestor-or-self axis contains the context node and the ancestors of
     * the context node; thus, the ancestor axis will always include the
     * root node.
     */
    public static final int ANCESTORORSELF = 1;

    /**
     * the attribute axis contains the attributes of the context node; the axis
     * will be empty unless the context node is an element.
     */
    public static final int ATTRIBUTE = 2;

    /**
     * The child axis contains the children of the context node.
     */
    public static final int CHILD = 3;

    /**
     * The descendant axis contains the descendants of the context node;
     * a descendant is a child or a child of a child and so on; thus the
     * descendant axis never contains attribute or namespace nodes.
     */
    public static final int DESCENDANT = 4;

    /**
     * The descendant-or-self axis contains the context node and the
     * descendants of the context node.
     */
    public static final int DESCENDANTORSELF = 5;

    /**
     * the following axis contains all nodes in the same document as the
     * context node that are after the context node in document order, excluding
     * any descendants and excluding attribute nodes and namespace nodes.
     */
    public static final int FOLLOWING = 6;

    /**
     * The following-sibling axis contains all the following siblings of the
     * context node; if the context node is an attribute node or namespace node,
     * the following-sibling axis is empty.
     */
    public static final int FOLLOWINGSIBLING = 7;

    /**
     * The namespace axis contains the namespace nodes of the context node; the
     * axis will be empty unless the context node is an element.
     */
    public static final int NAMESPACEDECLS = 8;

    /**
     * The namespace axis contains the namespace nodes of the context node; the
     * axis will be empty unless the context node is an element.
     */
    public static final int NAMESPACE = 9;

    /**
     * The parent axis contains the parent of the context node,
     * if there is one.
     */
    public static final int PARENT = 10;

    /**
     * The preceding axis contains all nodes in the same document as the context
     * node that are before the context node in document order, excluding any
     * ancestors and excluding attribute nodes and namespace nodes
     */
    public static final int PRECEDING = 11;

    /**
     * The preceding-sibling axis contains all the preceding siblings of the
     * context node; if the context node is an attribute node or namespace node,
     * the preceding-sibling axis is empty.
     */
    public static final int PRECEDINGSIBLING = 12;

    /**
     * The self axis contains just the context node itself.
     */
    public static final int SELF = 13;

    /**
     * A non-xpath axis, traversing the subtree including the subtree
     * root, descendants, attributes, and namespace node decls.
     */
    public static final int ALLFROMNODE = 14;

    /**
     * A non-xpath axis, traversing the the preceding and the ancestor nodes,
     * needed for inverseing select patterns to match patterns.
     */
    public static final int PRECEDINGANDANCESTOR = 15;

    // ===========================================
    // All axis past this are absolute.

    /**
     * A non-xpath axis, returns all nodes in the tree from and including the
     * root.
     */
    public static final int ALL = 16;

    /**
     * A non-xpath axis, returns all nodes that aren't namespaces or attributes,
     * from and including the root.
     */
    public static final int DESCENDANTSFROMROOT = 17;

    /**
     * A non-xpath axis, returns all nodes that aren't namespaces or attributes,
     * from and including the root.
     */
    public static final int DESCENDANTSORSELFFROMROOT = 18;

    /**
     * A non-xpath axis, returns root only.
     */
    public static final int ROOT = 19;

    /**
     * A non-xpath axis, for functions.
     */
    public static final int FILTEREDLIST = 20;

    /**
     * A table to identify whether an axis is a reverse axis;
     */
    private static final boolean[] isReverse = {
        true,  // ancestor
        true,  // ancestor-or-self
        false, // attribute
        false, // child
        false, // descendant
        false, // descendant-or-self
        false, // following
        false, // following-sibling
        false, // namespace
        false, // namespace-declarations
        false, // parent (one node, has no order)
        true,  // preceding
        true,  // preceding-sibling
        false  // self (one node, has no order)
    };

    /**
     * The names of the axes for diagnostic purposes.
     */
    private static final String[] names =
        {
            "ancestor",  // 0
            "ancestor-or-self",  // 1
            "attribute",  // 2
            "child",  // 3
            "descendant",  // 4
            "descendant-or-self",  // 5
            "following",  // 6
            "following-sibling",  // 7
            "namespace-decls",  // 8
            "namespace",  // 9
            "parent",  // 10
            "preceding",  // 11
            "preceding-sibling",  // 12
            "self",  // 13
            "all-from-node",  // 14
            "preceding-and-ancestor",  // 15
            "all",  // 16
            "descendants-from-root",  // 17
            "descendants-or-self-from-root",  // 18
            "root",  // 19
            "filtered-list"  // 20
        };

    public static boolean isReverse(int axis) {
        return isReverse[axis];
    }

    public static String getNames(int index) {
        return names[index];
    }

    public static int getNamesLength() {
        return names.length;
    }

}
